Doubtful Dandelion

There are quite a few plants that have that showy yellow head
Not all of them are Dandelions or ‘dent-de lion’ as it’s said
in French. The argument rages about what exactly the French meant
by that, the lion’s teeth part is straight forward (that’s the ‘dent’,
teeth) – de lion? Well, you can guess what that means. The problem is
where are these teeth? This would be something for a really good quiz
question. Some say the root, when cut shows white on black in stark relief.
The opposition (who I support) are sure it’s down to the shape of the leaf.